From 647e5d545792d7bc35a12cec8707d80363d49077 Mon Sep 17 00:00:00 2001
From: Hiroaki Yutani <yutani.ini@gmail.com>
Date: Thu, 27 Dec 2018 10:38:07 +0900
Subject: [PATCH 1/5] Add a failing test

---
 tests/testthat/test-stat-bin.R | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tests/testthat/test-stat-bin.R b/tests/testthat/test-stat-bin.R
index 8dc0b6f9c6..074e163104 100644
--- a/tests/testthat/test-stat-bin.R
+++ b/tests/testthat/test-stat-bin.R
@@ -69,6 +69,15 @@ test_that("breaks are transformed by the scale", {
    expect_equal(out2$xmin, sqrt(c(1, 2.5)))
 })
 
+test_that("geom_histogram() can be drawn over a 0-width range (#3043)", {
+  df <- data_frame(x = rep(1, 100))
+  out <- layer_data(ggplot(df, aes(x)) + geom_histogram())
+
+  expect_equal(nrow(out), 1)
+  expect_equal(out$xmin, 0.5)
+  expect_equal(out$xmax, 1.5)
+})
+
 # Underlying binning algorithm --------------------------------------------
 
 comp_bin <- function(df, ...) {

From 2b086318cb26e814d64cd61a8bb11cd5373dc69b Mon Sep 17 00:00:00 2001
From: Hiroaki Yutani <yutani.ini@gmail.com>
Date: Thu, 27 Dec 2018 10:40:17 +0900
Subject: [PATCH 2/5] Use the fixed binwidth when the range is 0-width

---
 R/bin.R | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/R/bin.R b/R/bin.R
index 654a01f98e..60fe9a21de 100644
--- a/R/bin.R
+++ b/R/bin.R
@@ -97,6 +97,8 @@ bin_breaks_bins <- function(x_range, bins = 30, center = NULL,
   bins <- as.integer(bins)
   if (bins < 1) {
     stop("Need at least one bin.", call. = FALSE)
+  } else if (zero_range(x_range)) {
+    width <- 1
   } else if (bins == 1) {
     width <- diff(x_range)
     boundary <- x_range[1]

From 38afc582f8ddd971ad9dc9939da552382a2eb089 Mon Sep 17 00:00:00 2001
From: Hiroaki Yutani <yutani.ini@gmail.com>
Date: Thu, 27 Dec 2018 11:10:12 +0900
Subject: [PATCH 3/5] Add a NEWS bullet

---
 NEWS.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index 313dc17df7..101def5842 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -27,6 +27,8 @@
 * `coord_sf()`, `coord_map()`, and `coord_polar()` now squash `-Inf` and `Inf`
   into the min and max of the plot (@yutannihilation, #2972).
 
+* `stat_bin()` now handles data with only one unique value (@yutannihilation #3047).
+
 # ggplot2 3.1.0
 
 ## Breaking changes

From a211badd1bf353190d035f05c94f9464b5667eff Mon Sep 17 00:00:00 2001
From: Hiroaki Yutani <yutani.ini@gmail.com>
Date: Thu, 3 Jan 2019 15:42:09 +0900
Subject: [PATCH 4/5] Use 0.1 for width

---
 R/bin.R | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/R/bin.R b/R/bin.R
index 60fe9a21de..dd1303a3ab 100644
--- a/R/bin.R
+++ b/R/bin.R
@@ -98,7 +98,8 @@ bin_breaks_bins <- function(x_range, bins = 30, center = NULL,
   if (bins < 1) {
     stop("Need at least one bin.", call. = FALSE)
   } else if (zero_range(x_range)) {
-    width <- 1
+    # 0.1 is the same width as the expansion `expand_default()` gives for 0-width data
+    width <- 0.1
   } else if (bins == 1) {
     width <- diff(x_range)
     boundary <- x_range[1]

From 156fd1b0ee0ff192ee00a9da2e8467e70e543026 Mon Sep 17 00:00:00 2001
From: Hiroaki Yutani <yutani.ini@gmail.com>
Date: Thu, 3 Jan 2019 15:44:24 +0900
Subject: [PATCH 5/5] Modify tests

---
 tests/testthat/test-stat-bin.R | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/testthat/test-stat-bin.R b/tests/testthat/test-stat-bin.R
index 074e163104..6da9671f83 100644
--- a/tests/testthat/test-stat-bin.R
+++ b/tests/testthat/test-stat-bin.R
@@ -74,8 +74,8 @@ test_that("geom_histogram() can be drawn over a 0-width range (#3043)", {
   out <- layer_data(ggplot(df, aes(x)) + geom_histogram())
 
   expect_equal(nrow(out), 1)
-  expect_equal(out$xmin, 0.5)
-  expect_equal(out$xmax, 1.5)
+  expect_equal(out$xmin, 0.95)
+  expect_equal(out$xmax, 1.05)
 })
 
 # Underlying binning algorithm --------------------------------------------